What is the normal function of the MTM1 gene?

The MTM1 gene provides instructions for producing an enzyme called myotubularin. Myotubularin is thought to be involved in the development and maintenance of muscle cells. This enzyme acts as a phosphatase, which means that it removes clusters of oxygen and phosphorus atoms (phosphate groups) from other molecules. Myotubularin removes phosphate groups from two molecules called phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-biphosphate. These molecules are found within cell membranes and are likely involved in transporting molecules within cells.

Does the MTM1 gene share characteristics with other genes?

The MTM1 gene belongs to a family of genes called PTP (protein tyrosine phosphatases).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? in the Handbook.

How are changes in the MTM1 gene related to health conditions?

More than 200 mutations in the MTM1 gene have been found to cause X-linked myotubular myopathy. Some MTM1 gene mutations change one of the protein building blocks (amino acids) in myotubularin, while other mutations result in an abnormally short, nonfunctional enzyme. The MTM1 gene mutations that prevent the production of any functional myotubularin tend to result in a more severe disease. Individuals who are mildly affected tend to have an MTM1 mutation that allows some functional myotubularin to be produced.

Mutations in the MTM1 gene are thought to disrupt myotubularin's role in muscle cell development and maintenance, causing muscle weakness and other signs and symptoms of X-linked myotubular myopathy.

The resources on this site should not be used as a substitute for
professional medical care or advice. Users seeking information about
a personal genetic disease, syndrome, or condition should consult with a qualified
healthcare professional.
See How can I find a genetics professional in my area? in the Handbook.